George I walnut stick barometer.

Like many good barometers of this early period this piece is unsigned. Domestic barometers were increasing in popularity and were made by optical and scientific instrument-makers as well as clockmakers. The workings of a stick barometer are fairly simple. A glass tube sealed at one end is glued to a bowwood cistern at the other. The tube is filled with mercury and the cistern capped usually with a threaded end-piece, the tube is inverted and a vacuum is created at the top. Barometric pressure keeps the mercury somewhere around 30” as witnessed by the engraved scale to the right. The limitations of a barometer for accurately predicting weather were well understood. Richard Neve in his “Baroscopologia” in 1708 noted sixteen natural phenomena that should be used in conjunction with the barometer including, “Hoggs crying in an unusual manner and running unquietly up and down..” and “If crows caw and cry early in the morning, with a loud clear voice, it shews that the day will be fair.” Descriptions of weather to be expected are engraved on the scale to the left.
The boxwood cistern has a leather bottom, which the brass screw underneath the cistern cover pushes against when turned clockwise. This pushes the mercury up the tube until the vacuum is filled, which then enables easier transportation. This system was invented by the eminent clockmaker Daniel Quare though his exact design is not recorded.
The carcass is pine veneered in walnut with solid walnut mouldings and cistern cover. An unusual feature is the pierced wooden tube cover running from the top of the cistern cover to the bottom of the scales. The brass engraved and silvered scales are protected by a glazed brass door.
“The baroscope is an instrument well known to most men; few gentlemen being without one of them, though few of them understand its right management and use..” Richard Neve, Baroscopologia, 1708.